7_editing_first_app

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In the last lecture,

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we created our first Angular app,

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but we haven't changed anything there.

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So time to do that.

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And for that,

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you need an IDE or editor where you can write and edit your code.

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Now I'm using WebStorm here.

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WebStorm is a great IDE,

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great for Angular development,

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but it's not free.

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A great free alternative would be Visual Studio Code,

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which you can find on code .visualstudio .com.

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This is a great IDE and it is free.

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You can simply download and install it,

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both for Mac and Windows.

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And then you can start developing Angular with that.

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Whichever IDE or editor you install,

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you'll always have to open a new folder.

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In WebStrom case,

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it's just called Open.

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And then simply navigate to the folder you created.

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So in my case here,

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it's my first app.

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Select that folder and open it.

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And now it will load that folder and all the files into the IDE on

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your system.

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So in my case,

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it now looks like that.

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Now this is the project loaded into the IDE.

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Now it's still indexing it here,

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but it'll be done in a second.

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And these are all the folders and files the Angular CLI

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created for you.

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This is your entire Angular project.

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Now,

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as I said, this might look intimidating because you got so many files

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in there.

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Most of these files are just doing some configuration work and you don't really need to touch

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them. One interesting file is the package .json file.

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Here you can see all the dependencies of your project like Angular 6.

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And these are these third party packages your project

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needs to run correctly.

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All dev dependencies are only required for development for this build

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workflow I was talking about.

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but we're here to edit our code right so let's jump into the source

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folder because that is where our code is e2e is for end -to -end testing we'll

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ignore this and node modules is where all these dependencies you see in the package .json

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file actually were installed but we're interested in the source code so let's

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go to source then we got a bunch of other configuration files and

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then here we got this app folder and in this app folder we

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see some other files

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of course i'll dive into what they all do in detail in this course and

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for now let's open the app component html file and here we

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indeed see something which looks deceivingly like what we saw in the browser

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do you remember it's welcome to app and so on we

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see that here too

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By the way,

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make sure you keep that localhost 4002 process running.

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So that ng -surf process you started here in the terminal.

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Make sure to keep that running.

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If you're done with development for the day,

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you can quit it with control C and you'll get out of there.

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But as long as you are developing,

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you should keep it running because it will automatically watch your files and

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rebuild your project whenever you change and save something.

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Now, since I quit it,

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I'll need to restart it.

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And I will actually restart it here.

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In my IDE,

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there's a built -in terminal,

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but it's the normal system terminal.

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So here I can also run ng -surf to bring that back up.

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But back to the app component HTML file,

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we're outputting something here.

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And if we change anything here like,

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hi,

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this is instead of welcome to,

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and we save that with ng -surf running,

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if you go back,

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you see it automatically updated,

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hi,

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this app.

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Now, one strange thing we see is that this app here,

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well,

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we actually only see these curly braces and title in the app

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component HTML file.

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And therefore,

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we can already see some of the work Angular does here.

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Angular is,

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of course, not a tool to allow us to write static HTML files.

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We would need no framework for that.

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It allows us to mix static HTML code and

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dynamic things we want to output in that code.

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And actually,

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what we have here is one of these components Angular works with,

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the app component.

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A component always has a template,

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the HTML code.

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possibly has some stylings in the CSS file,

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though it's empty here,

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as you can see.

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And importantly,

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it has a TypeScript file.

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If we enter this,

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this is TypeScript.

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And this is now the definition of the component.

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This is what will be converted to normal JavaScript by the build workflow.

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And in this file,

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we see a couple of interesting things like add component.

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I'll come back to that and what in detail is happening here in the next module.

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We also see title equals app.

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Now,

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what's that?

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If we go back to the app component HTML file,

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we also saw a title here,

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right? Between the curly braces.

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So an assumption would be that the title

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in the TypeScript file is related to that.

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So let's maybe change this to my app.

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And now if we save this,

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it recompiles.

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And if we go back,

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we see, hi,

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this my app.

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Now this might not be perfect English,

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but we can definitely see that something changed.

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The so -called data binding in action.

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Of course,

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all the concepts will dive in deeply in this course.

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And this is how we can output dynamic content.

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And this could,

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of course, be content that is calculated dynamically or retrieved from a server in

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our HTML code.

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Now,

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interesting, if we right click on the loaded page and inspect the

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page source.

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We don't actually see that code there.

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We just see a bunch of script imports at the bottom.

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That is our build code and the Angular framework code.

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The head tag here.

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And then this strange app root part.

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Now app root is also something we see

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in the app component TypeScript file.

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Here,

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the selector.

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So it looks like this is basically like our own HTML tag

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we're creating.

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And that's indeed what's happening here.

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The page we're viewing here to which the source belongs actually

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is this index .html file in the source folder.

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Here we also see app root.

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The script imports are missing because they are injected dynamically.

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Now, what Angular does in the end is we always load this page,

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then we have these dynamically injected script imports and these script

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imports will dynamically replace app root with our own component.

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And of course,

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we can have more than one component in Angular apps.

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Again, these are all things we'll dive into in this course.

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Now that's all nice.

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Let's do something more fancy.

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Let's change title dynamically.

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So back in the app component,

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I'll actually get rid of the entire code in here and I'll add an input instead,

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a normal HTML input,

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type text.

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Below that,

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I'll add a paragraph where I want to output,

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let's say a name.

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Now name is not something we defined yet.

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We'll do so in a second.

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Let's go to app component and let's change title to name and

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I'll say max here because that is my name.

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And if I save that,

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I go back.

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We see the input and we see the name.

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Now I want to be able to enter something in the input and automatically change the

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name. We can do this with a tool provided by Angular,

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a so -called directive,

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which is called ng -model.

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Now you'll learn the exact syntax throughout the course.

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For now, let's simply add square brackets,

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parentheses,

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ng -model,

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written like that.

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Make sure to get the casing correct.

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There is no dash in between or anything like that.

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So ng -model in square brackets and parentheses,

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on the input and set it equal to name.

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So to the same name you're outputting here.

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Now this is so -called directive and what it does is it basically

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tells Angular to listen to anything you enter here

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and store it in this name property,

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in this name model,

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but also on the other hand,

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output the value of the name model in this input.

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This is what we're doing here.

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Now,

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if we save this,

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we don't see anything on the page and if we open the developer tools

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which you can simply do from the menu or with the shortcut.

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You reach it under view,

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developer,

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developer tools in Chrome.

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And I strongly recommend using Chrome for this course since it has the best developer

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tools.

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So then we see here in the console part,

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there's an error.

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Can't bind to ng -model since it isn't a known property of input.

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So somehow Angular doesn't understand ng -model.

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Now that's strange because I said it's built in,

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right? Angular is actually split up into multiple modules.

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sub packages,

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you could say.

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And we need to add them if you want to use a certain feature from

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them. And in this course,

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you will learn about the different packages and which features they contain.

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To add such a feature,

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we go to that other file we haven't had a look at yet,

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the app module.

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This is basically where we tell Angular which pieces belong

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to our app.

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And there we have to add something to imports to import another package

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from Angular.

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So we need to import it at the top of the file first because TypeScript always

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needs to know where things are.

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So we import something from,

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and then it's at angular slash forms.

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This is one other package from the Angular framework.

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And from that package,

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we can import the forms module written like this.

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So make sure to add this import.

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This is not an Angular feature,

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but a TypeScript feature.

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As I said,

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TypeScript needs to know where the things are.

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But now with that imported,

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we can add it to this imports array down here,

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which is not related to the imports up there.

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This is simply a feature understood by Angular,

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since it's part of an Angular module.

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And now it tells Angular that we want to import some forms features.

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And this directive we're using is such a form feature.

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So now if we save that,

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our app will rebuild.

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And once it is done,

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we can go back and now we see our input and there's max inside of it.

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And if I start typing there,

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you see that the text below it automatically also updates.

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This is some magic done by ng -model.

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We'll dive much deeper into everything we learned here,

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but this is now our first app with some changes.

7_editing_first_app

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